The present disclosure relates generally to drive disks, and more particularly, to head gimbal assemblies and methods for measuring slider parameters.
Disk drives are used to store and retrieve data in many electronic devices including computers, televisions, video recorders, servers, digital recorders, etc. A typical disk drive includes a head having a slider and a transducer with read and write elements in close proximity to the surface of a rotatable magnetic disk. As the magnetic disk rotates beneath the head, a thin air bearing is formed between the surface of the magnetic disk and an air bearing surface (ABS) of the slider. The read and write elements of the head are alternatively used to read and write data while a positioner arm positions the head along tracks on the magnetic disk. The tracks on the magnetic disks are typically concentric circular regions onto which data can be stored by writing to it and retrieved by reading from it.
A suspension assembly connects the slider to the positioner arm. The suspension assembly includes a load beam and a flexure which allows the slider to gimbal with respect to the load beam. The load beam and the flexure are fabricated separately and then joined together. The head is then joined to the flexure. The joined assembly comprising the load beam, the flexure and the head is known as a head gimbal assembly (HGA). The HGA supports the slider at the correct height above the rotating disk and allows the slider to pitch and roll so that it can follow the topology of the rotating disk.
The position of the slider with respect to the rotating disk can have a direct impact on performance. Preferably, the slider should be configured to fly as close to the disk as possible without coming into contact with the disk. The closer the slider can fly over the disk, the more densely the data can be stored due to an increase in the magnetic field. However, if the disk comes into contact with the disk, damage may occur to both the transducer and the disk, along with the information stored on the disk. In order to achieve the appropriate position, the HGA is typically designed to balance the load applied to the slider against the upward lift of the air stream below the slider. The HGA is typically designed so that the slider can adjust quickly to surface undulations of the disk with pitch and roll reduced to acceptable levels.
Various methods exist for determining slider motion for test, design, and failure analysis. One method involves projecting a laser beam onto the ABS of the slider from under a transparent glass disk. However, since the glass disk is not the same as the magnetic disk used in disk drives, the interference between the head and the disk may be different. Also, measuring slider motion through a transparent disk requires special experimental setup but still cannot perfectly duplicate the drive operating conditions when the slider is flying over a magnetic disk.
Therefore, what is needed is a system and method to measure slider motion under actual operating conditions without a transparent disk.